[Bug pch/61250] Random pch failures on x86_64-apple-darwin1(3|4).

[howarth at bromo dot med.uc.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61250

--- Comment #7 from howarth at bromo dot med.uc.edu ---
Is there any sensible approach we can use to try to obtain a backtrace?